Pompeo's visit is part of a whistlestop regional tour aimed at reassuring US allies after President Donald Trump's shock decision to withdraw all US troops from Syria.

The US top diplomat flew in to Manama from Cairo and has already visited Amman, Baghdad and the Iraqi Kurdish regional capital of Arbil.

He will also visit the other five members of the Gulf Cooperation Council -- the United Arab Emirates, Qatar, Kuwait, Oman and Saudi Arabia.

State Department officials have said Pompeo hopes his trip will strengthen the GCC, which has been weakened by a diplomatic rift that has pitted Saudi Arabia and its allies against Qatar for more than 18 months.

They accuse Doha of supporting groups blacklisted as "terrorist" by the GCC and of advocating improved ties with Iran.

Doha, which is home to a huge US air base, has denied the claims.

The State Department has said that a "united Gulf Cooperation Council the backbone for regional peace, prosperity, security and stability" and key to countering Iran.

It said Pompeo would also work with regional leaders to advance a proposed Middle East Strategic Alliance -- a NATO-style security pact.

During his talks in the Gulf, Pompeo is also expected to discuss the conflict in Yemen where a Saudi-led coalition has been fighting Iran-linked rebels since March 2015 despite a growing international outcry over the human cost.